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Colowyo, C1981-019, PR3 adequacy 11 February 25, 2011 <br />The DRMS will complete its review of the proposed hydrologic monitoring plan after receiving the <br />requested calculations of pitwall seepage and spoil spring discharges. <br />Rule 2.06.8 Alluvial Valley Floor Determination <br />1. Significant reference to Dames and Moore (1980, 1995) and Walsh (1984) studies regarding <br />Alluvial Valley Floor investigations are found within Permit Revision No. 3. Efforts to find <br />these studies in the original Colowyo permit have however been unsuccessful. Please re- <br />submit the Dames and Moore (1980, 1995) and Walsh (1984) studies or reference where in the <br />existing permit they are located. <br />2. The last paragraph, page 6 in Exhibit 7, Item 24 says that "final conclusions will be presented <br />following our review of the data remaining to be collected". Maxim compiled this document in <br />September of 2005; has more data been collected since then? If so, please provide that data. <br />3. Referring to Table 1 in Exhibit 1, Item 24, the West Jubb Drainage Alluvial Monitoring Well is <br />labeled MJ 95-01 and on the Map (Figurel) Valley Fill Deposits. The East Jubb Drainage is <br />labeled MJ 95-02 on Figure 1, but in Table 1 is called West Jubb. Please change the name of <br />the drainage in Table 1 to East Jubb for Well ID MJ 95-02. <br />4. Sections of Collom Gulch have been previously identified by the Office of Surface Mining as <br />potentially irrigable based on water availability sufficient for irrigation development consistent <br />with regional agricultural practices. Although Maxim referenced this OSM 1985 <br />Reconnaissance Map to assist in Alluvial Valley Floors, they do not go into great detail about <br />Collom Gulch and its potential to be an alluvial valley floor downstream. Please amend the <br />text with more discussion of Collom Gulch, specifically a discussion on the value to <br />landowners downstream. <br />5. According to Rule 2.06.8(3)(b)(iii), mapping of all lands subject to agricultural activities, <br />showing different types of agricultural lands and measurements of vegetation terms of <br />productivity and type, is required. In the Land Use Map 17, it shows that downstream of <br />Collom Gulch, north of the permit area there is some Cropland. In the Vegetation Map 4C <br />(Sheet 1 of 11) it shows that the same area is Bottomland. Looking at the Bottomland <br />Vegetation Information outlined in Section 2.04.10, page 61 of the permit application, <br />describes Bottomland vegetation to be comprised of sagebrush, mountain shrub and grasslands. <br />Does the Bottomland have agricultural significance? <br />6. The Division requests that an alluvial monitoring well be installed downstream in Collom <br />Gulch, north of the permit area and Highway 32,. This area is a documented alluvial valley <br />floor according to the OSM 1985 Reconnaissance Map, and because of its close proximity to <br />the permit area it would be beneficial to have baseline data and long term monitoring <br />throughout the life of mine. According to Rule 4.24.3(3), surface coal mining and reclamation <br />operations shall not cause material damage to the quality or quantity of water in surface or <br />underground water systems that supply alluvial valley floors. According to Rule 4.24.4(1), an